MS-6368 (OEM by Compaq) may died

I did an fresh install of Windows XP Home, installed Windows updates and driver updates.
I restarted the system and everything was been fine.

At last I deactivated the onboard TridentBlade graphic chipset via Hardware Manager. (like it was been before)
Because I'm using a GeForce2 MX400 @ PCi. (is working since a year in this PC)

Well, I had to restart the system and now I just get an Error Code by the mainboard speaker.

It's an continuous short bleep and it doesn't stop until I switch of the PC.
BIOS is made by Award. And so far I know, the Error Code is saying there is a problem with energy supply of mainboard.
I have no idea what happen, I tried also another PowerSupply of a working PC. But still no joy.
Even the screen keeps black.

Not much left to try. There's a chance the second power supply is not working, but if it came from a working system, that would not be the case. Any other video card to try, in case the onboard is bad and the MX400 is also bad? You can also try the motherboard outside the case on a cardboard box, but if that doesn't work, the motherboard may have gone bad.

The bad thing is I can't try another videocard. It's not possible to disable the onboard graphic by BIOS because of used Chipset. (I've checked the mainboard manual)

So, I could install any PCi videocard, the board would boot with the onboard one. But WinXP is swapping to the PCi one then. I'm just be able to get a boot screen if screen is connected to onboard vga.

The 5 R's
1. Repair
2. Restore
3. Reinstall
4. Remote admin
5. Run away
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